The present invention relates generally to plow assemblies adapted to ride on the surface of a conveyor belt and, more particularly, to such plow assemblies which include means for raising one or more plows of the plow assembly from the surface of the conveyor belt to facilitate, among other things, cleaning of the plows.
While the present invention will be discussed hereinafter with reference to its use in conjunction with a conveyor type filtering device used for dewatering of sludge, it should be recognized that its use and applicability are not thereby so limited.
A belt-type filtering device used for the dewatering of sludge generally comprises an endless, liquid permeable conveyor belt supported in a generally horizontal position by a perforate guide table. Sludge is deposited on the horizontal belt at one end of the device and as the belt travels, water continually passes through the perforate belt to yield a dewatered sludge at the other end of the device.
It has been found that dewatering in such a device is enhanced if one or more so-called "plows" are fixed above the belt so as to extend into the moving sludge and contact the upper surface of the belt. Such plows tend to evenly distribute the sludge over the surface of the belt, help prevent the formation of solid material layers, and also tend to keep the perforations in the belt open by scraping over or wiping the top surface of the belt. To prevent damage to the plows by impact with large obstacles which may be contained in the sludge, it has been a practice of some to have the plows pivotally mounted on the filtering device such that the plows are capable of pivoting upwardly out of the sludge upon contact with an obstacle.
One problem that has been encountered in the use of plows in conjunction with conveyor-type filtering devices is that, after relatively long periods of use, the plows become encrusted with various matter contained in the sludge and thus, among other things, do not perform their scraping function adequately. In order to clean the plows such as by water spraying, operation of the filtering device must be discontinued, especially in the case of fixed plows. In the case of pivoted plows, if continuous operation of the device is desired, each plow must be pivoted individually for cleaning. Either practice is inefficient and/or time-consuming.